Antimatter at CERN

With some echos of Dan Brown’s fictious novel, CERN have successfully managed to create and then trap antihydrogen atoms.

Not quite sure what they are? OK, its like this … these antiparticles are simply the oppositely charged twins of normal particles.

Generating antihydrogen has of course been done before, that’s not new. What is different here is that they have managed to trap the particles for the first time. Now an experiment called the Antihydrogen Laser Physics Apparatus (ALPHA) at the CERN particle physics laboratory near Geneva, Switzerland, has finally managed to ensnare atoms of antihydrogen. What they did was to combine antiprotons from CERN’s Antiproton Decelerator ring with positrons emitted by a radioactive isotope of sodium … then … this is the new bit … they manipulated the anti-atoms magnetically.

the ALPHA team members tried to create sluggish anti-atoms by bouncing antiprotons at -70 °C off much colder positrons at -230 °C. The antiprotons lost energy in the collisions before some finally combined with the positrons to form antihydrogen. The slowest anti-atoms, at a temperature of just -272.5 °C, then became trapped in a powerful cylinder-shaped magnetic field created by superconducting magnets. The field was then turned off so the antihydrogen could annihilate with normal matter, creating particles that silicon detectors picked up.

Now don’t get too excited here … this is not about the creation of an antimatter device for military use. Having done this experiment over 335 times, they only ended up with 38 of these antihydrogen atoms. This now puts them in the position of being able to test whether anti-atoms obey the same physical laws as regular atoms. For example, matter and antimatter should absorb and emit light at the same wavelengths, according to the standard model of particle physics.

This is an encouraging step towards the goal that I laid out long ago – to confine useful numbers of cold antihydrogen atoms long enough for precise laser spectroscopy,” says Gerald Gabrielse of Harvard University. He heads a rival experiment at CERN called ATRAP.

If the spectrum of antihydrogen does not match that of ordinary hydrogen, it would leave the standard model in disarray. But any discrepancies could shed light on the long-standing mystery of why the universe is dominated by matter when the big bang should have created equal amounts of matter and antimatter, Gabrielse says.

You can read more about all this in New Scientist by clicking here.

So, Dan Brown aside, its exciting stuff and allows us to push the boundaries of our understanding even further.

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